THE SKELETON 21 



vomer, part of which is bony and part carti- 

 laginous. 



Though the mandible appears to be a single 

 bone, it is really composed of right and left 

 bones, each developed from five elements. 

 The articular forms the posterior part of the 

 mandible and is expanded. It carries a 

 slightly concave surface for articulation with 

 the quadrate, behind which the lower border 

 of the bone is continued as a process with a 

 curve in an upward direction. Continuing 

 the articular forwards is the remains of Meckel's 

 cartilage, the original cartilaginous bar of the 

 mandibular arch, about which the remaining 

 elements of the mandible are developed. The 

 angular is a slender strip of bone lying below 

 the articular and along the lower border of 

 the jaw. The posterior third or more of the 

 upper border of the mandible is formed by 

 the supra-angular, on which there is a very 

 small coronoid process a little anterior to the 

 articular surface for the quadrate. The splenial 

 is a thin plate of bone lying along the inner 

 face of the mandible. The largest element of 

 the mandible is the dentary, which forms the 

 anterior half of the jaw and fuses firmly with 

 its fellow of the opposite side. 



